1. Field of the Invention
The present invention relates generally to fluid delivery devices. More particularly, the invention concerns an improved apparatus having a light activated energy source for infusing medicinal agents into an ambulatory patient at specific rates over extended periods of time.
2. Discussion of the Invention
The oral route is the most frequent route of drug administration. Oral administration is relatively easy for most patients and rarely causes physical discomfort. However, many medicinal agents require a parenteral route of administration thus bypassing the digestive system and precluding degradation by the catalytic enzymes in the digestive tract and the liver. The use of more potent medications at elevated concentrations has also increased the need for accuracy in controlling the delivery of such drugs. The delivery device, while not an active pharmacologic agent, may enhance the activity of the drug by mediating its therapeutic effectiveness. Certain classes of new pharmacologic agents possess a very narrow range of therapeutic effectiveness, for instance, too small a dose results in no effect, while too great a dose results in toxic reaction.
In the past, prolonged infusion of fluids has generally been accomplished using gravity flow means coupled with electronic based controls and typically involve the use of intravenous administration sets and the familiar bottle or solution bag suspended above the patient. Such methods are cumbersome, imprecise and, generally non-ambulatory requiring bed confinement of the patient. Periodic monitoring of the apparatus by the nurse or doctor is required to detect malfunctions of the infusion apparatus.
Devices of the character from which liquid is expelled from a relatively thick-walled bladder by internal stresses within the distended bladder have also been suggested for infusion of medicaments. For example, such bladder, or xe2x80x9cballoonxe2x80x9d type devices, are described in U.S. Pat. No. 3,469,578, issued to Bierman and in U.S. Pat. No. 4,318,400, issued to Perry.
A family of highly unique fluid delivery devices has been developed by the present inventor. These novel devices make use of recently developed elastomeric films, expandable foams and similar materials, which, in cooperation with a base define a fluid chamber that contains the fluid to be dispensed. The elastomeric film membrane or the expandable member controllably forces fluid within the chamber into outlet fluid flow channels provided in the device. Elastomeric film membrane devices are described in detail in U.S. Pat. No. 5,205,820 issued to the present inventor. U.S. Pat. No. 5,468,226, also issued to the present inventor, describes various types of expandable cellular elastomers and elastomeric foams used as the energy source of the fluid delivery device for expelling fluid from various physical forms of the fluid delivery device. Because of the pertinence of Pat. Nos. 5,205,820 and 5,468,226, these patents are hereby incorporated herein by reference in their entirety as though fully set forth herein. Copending U.S. application Ser. No. 08/541,030, filed Oct. 11, 1996 in which the present inventor is named as co-inventor, is also pertinent to one form of the apparatus of the invention which is described hereinafter. Accordingly, Ser. No. 08/541,030 is also hereby incorporated by reference as though fully set forth herein.
U.S. Ser. No. 08/919,147, now U.S. Pat. No. 5, 961,492 is also incorporated by reference as though fully set forth herein.
The apparatus of the present invention, which takes various physical forms, makes use of novel light activated expansive material as an energy source. This family of devices can also be used with minimal professional assistance in an alternate health care environment, such as the home. By way of example, devices of the invention can be comfortably and conveniently removably affixed to the patient""s body and can be used with or without remotely located infusion sets for the continuous infusion of antibiotics, hormones, steroids, blood clotting agents, analgesics, and like medicinal agents. Similarly, the devices can be used for I-V chemotherapy and can accurately deliver fluids to the patient in precisely the correct quantities and at extended microinfusion rates over time.
One of the embodiments of the present invention comprises an ambulatory fluid dispensing system which includes a relatively thin body attached rigid base assembly and a uniquely designed stored energy means which cooperates with the base assembly for controllably expelling fluid from the reservoir of the device. In this form of the invention, the stored energy means is provided in the form of a light activated gel, the nature of which will be described in greater detail hereinafter. In this particular form of the invention, a novel, remotely located infusion set can be quickly coupled to the base assembly to enable precise infusion of fluid to a patient upon stimulation of the expandable gel by the gel stimulation means of the invention.
Another embodiment of the invention comprises an ambulatory, programmable fluid dispensing system which includes a rigid base assembly and a uniquely designed stored energy means which cooperates with the base assembly for controllably expelling fluid from the reservoir of the device. In this latter form of the invention, the stored energy means is also provided in the form of an expandable gel. A disposable infusion set can be quickly coupled to the base assembly to enable precise infusion of fluid to a patient upon stimulation of the expandable gel caused by operator energization of a battery powered light source.
Another embodiment of the invention comprises an implantable programmable fluid delivery device that also includes an expandable gel which acts as the stored energy means. The expandable gel can be activated by a source of light to cause the gel to controllably expand and expel fluid from the device reservoir through a novel cannula assembly.
The primary thrust of the invention described herein is to provide novel expandable gel type fluid delivery systems that are compact, easy to use, relatively low profile and are eminently capable of meeting even the most stringent of fluid delivery tolerance requirements. In this regard, medical and pharmacological research continues to reveal the importance of the manner in which a medicinal agent is administered. For example, certain classes of pharmacological agents possess a very narrow dosage range of therapeutic effectiveness, in which case too small a dose will have no effect, while too great a dose can result in toxic reaction. In other instances, some forms of medication require an extended delivery time to achieve the utmost effectiveness of a medicinal therapeutic regimen.
It is an object of the present invention to provide a technically advanced, fluid delivery apparatus for infusing medicinal fluids into a patient that is of a compact, low profile, laminate construction. More particularly, it is an object of the invention to provide an apparatus of such a character which embodies a novel expanding and contracting polymer gel material which uniquely functions as an internal energy source for expelling the medicinal fluids from the device.
Another object of the invention is to provide a fluid delivery device of the character described in the preceding paragraph that can be implanted into the body of the patient.
Another object of the invention is to provide an ambulatory fluid delivery apparatus that can conveniently be used for the precise infusion of various pharmaceutical fluids in accordance with specific therapeutic protocols into an ambulatory patient at controlled rates over extended periods of time.
Another object of the invention is to provide an apparatus of the aforementioned character that is highly reliable and easy-to-use by lay persons in a non-hospital environment.
Another object of the invention is to provide an apparatus that embodies as its stored energy source, a soft, pliable, semi-solid, light activated medium which is activated by a novel light source in a manner to controllably expel fluid from the device over time.
Another object of the invention is to provide an apparatus as described in the preceding paragraph in which the light activated energy source is specifically tailored to provide precise, predictable protocol delivery including pattern delivery of the medicinal agent stored within the reservoir of the device.
Another object of the invention is to provide a fluid delivery system of the class described that includes an interactive sensor means for sensing physiological conditions, such as blood glucose level and patient chemistry.
A further object of the invention is to provide a low profile, fluid delivery device of laminate construction which can meet even the most stringent fluid delivery tolerance and flow signature requirements.
Another object of the invention is to provide stored energy sources of the character described in the preceding paragraph which comprise blends or laminate constructions of phase transition gels that will enable the achievement of multi-rate and multi-frequency delivery protocols.
Another object of the invention is to provide an apparatus of the character described which includes a novel, combination filter and rate control assemblage disposed intermediate the fluid reservoir and the outlet port of the device or intermediate outlet port of the device and the infusion means.
Another object of the invention is to provide an apparatus of the character described which, due to its unique construction, can be manufactured inexpensively in large volume by automated machinery.
Other objects of the invention are set forth in U.S. Pat. Nos. 5,205,820 and 5,468,226, which patents are incorporated herein by reference. Still further objects of the invention will become apparent from the discussion that follows.